Parenteral drug therapy first was used in experiments over three hundred years ago. In 1656, Christopher Wren using a quill and a bladder injected intravenously opium into dogs. Six years later, in 1662, Johnann Daniel Major performed the first successful intravenous administration of an elusive "medical substance" for anesthetic purposes in humans. An animal suffering from a loss of blood was restored, in 1662, by an infusion of blood from another animal, and shortly thereafter in 1667, a Parisian boy was the first human to receive a blood transfusion. About 200 years later in 1832, Thomas A. Latta infused intravenously large volumes of saline solution into cholera victims, and although his efforts met with some success, serious complications arose from infections, and death was a frequent outcome. From this time until the twentieth century, intravenous administration virtually stopped because the procedures used were unsterile and the blood was unmatched, which conditions led to fatal results. In 1920 Karl Landsteiner established the major blood groups, and around 1923, with the discovery and elimination of pyrogens, coupled with the use of sterile techniques, the administration of parenteral fluids intravenously became safer and more frequent. Today the parenteral administration of sterile fluids is an established clinical practice, and this practice is used extensively as an integral part of the daily treatment of medical and surgical patients.
The fluids administered parenterally, usually intravenously, include aqueous solutions of dextrose, sodium chloride, and various other electrolytes. Blood and blood substitutes are always administered intravenously. Generally, the fluids are administered from a container that is suspended above the patient, with the fluid flowing from the container through an administration set and thence to a cannula or a hypodermic needle placed in a blood vessel, usually a vein. For intrapertioneal administration of fluids, the administration set is connected to a cannula traversing the abdominal wall of the patient.
The administration of fluids parenterally is a valuable and important component of patient care. The use of parenteral fluids moreover has in recent years expanded beyond its original role of fluid and electrolyte replacement to include serving as a vehicle for the parenteral administration of various beneficial agents, including drugs. Notably, the expanded use has occurred where it is desirable to administer a single drug by infusion via the intravenous, intra-arterial, intraperitoneal or subcutaneous routes; however, the expanded use has not occurred where it is desirable to administer more than one drug, mainly because the prior art has not provided a delivery system for this purpose, and because of the potential incompatibility of some drugs. Presently, a single drug is administered, for example, intravenously by one of the following procedures: temporarily halting the flow of medical fluid and intravenously administering a solution of drug to the patient through an injection port in the administration set, followed by resumption of medical fluid into the patient; a drug is added to the fluid in the container, or into a volume control chamber in series with the administration set, and then carried by the flow of fluid into a patient; a drug is introduced into a piggyback container, which is subsequently connected through a connector, in tributary fashion, to the primary administration set through which fluid is administered to the patient; or a drug is administered by a pump which, by one of various recognized pumping actions, establishes flow and this determines the flow of fluid containing the drug into a flow path entering the patient, for example, an indwelling venous catheter.
While the prior art has provided delivery systems and procedures for administering a single agent to a recipient, the prior art heretobefore has not provided a parenteral delivery system that can be used clinically for administering parenterally (a) a single agent according to a preselected program comprising continuous administration, repeated administration, administration at specific intervals, or as needed administration; and, which parenteral delivery system also can be used clinically for administering parenterally (b) more than one agent according to a preselected program comprising concurrent administration, successive administration, or alternating agent administration. It will also be apparent in view of the above that a pressing need exists for a parenteral delivery system that is both dependable and practicable for delivering more than one agent while simultaneously lessening the possibility of agent incompatibility that can occur when more than one agent is administered to a recipient at a controlled rate and in a beneficially effective amount over time.